"IPv6 adoption is like the classic chicken-egg circle, where if ISPs would make IPv6 available to their customers, hosting companies and major Websites might make their sites work with IPv6, and vice versa," Clift commented.

Vixie said the challenges to adoption of IPv6 are also technical. He noted that all of ISC's public facing services, including its DNS services, are dual stack
IPv4 and IPv6, and have been for several years.

"We are a classic early adopter and also, in the case of IPv6 DNS services, an early specifier implementor," Vixie said.

The ISC does not have an official position on IPv6 barriers, but Vixie's view is that the IETF has dropped the ball on IPv6.

"The original IPv6 goal sheet said that it would be fully interoperable with
IPv4 and that an incremental upgrade would be possible such that the transition from IPv4 to IPv6 would be soft and there would be no flag day,"
Vixie said. "None of those promises have been fulfilled."

Removing roadblocks to IPv6-only Internet access is important, he added, but so is the issue of how other players upgrade, too.

"No one can be IPv6-only until everybody else is dual stack, IPv4 and IPv6,"
Vixie explained. "Meanwhile the economic model is inverted, such that deploying dual-stack (IPv4 and IPv6) brings no benefit to the deployer, it only benefits the community."

Vixie argued that the only reason people will deploy a dual IPv4 and
IPv6 stack is to deal with the looming shortage of new IPv4 address space.
That's why everybody wants to use IPv4 for as long as possible.

"No one wants to abandon it (IPv4) and adopt the higher cost of dual stack or IPv6-only until everyone else is forced to do the same," Vixie said.
"This isn't a particular barrier it's a general malaise, having its roots in the impedance mismatch between IPV6 technology and internet economics."

VeriSign, which operates a key part of the DNS structure was not immediately available for comment.